I put a couple hundred pics on this thumb drive and I have no problems accessing any part of the drive. The only problem is all the programs I have for viewing jpegs say that about half of them can't be read. My computer identifies them as jpegs, but half (and they all came from the same road trip using the same phone (Samsung S7) to snap the pics with) say that can't be read.

When I try to open them in Adobe Photoshop I get a message saying "Could not complete your request because an unknown or invalid JPEG marker type is found." I have no idea what they mean. Here is one of the good files:

landscape from Canada

But I see no way to upload one of the jpegs that can't be recognized.

I'm fairly confident the drive is in good working order. I copied them from the Samsung S7 to the drive. I have other pics on my computer from the same camera and none have the problem. But like I said, I can't find any bad sectors or problems with my thumb drive.

  • 3
    Is the thumb drive the original source? If not, did you check the originals? It wouldn't be the first time in history a flash drive corrupted data.
    – Tetsujin
    Jul 22 '19 at 8:22
  • 3
    Possible duplicate of Why do images get "corrupted"?
    – mattdm
    Jul 22 '19 at 9:01
  • I'm fairly confident the drive is in good working order. I copied them from the phone to the drive and the phone was a Samsung S7. I have other pics on my computer from the same camera and none have the problem? But like I said I can't find any bad sectors or problems with my thumb drive? Oh and Tetsujin thank you for the info on where to let them know about the non functional links. :) So is that what it means when Photoshop says an invalid jpeg marker was found?? Does that mean it's corrupt? I was hoping some other program might be able to read them?? Jul 22 '19 at 19:08
  • 1
    It might just be a faulty or incomplete transfer. Have you tried recopying the file from the phone? These types of glitches happen, which is why some people insist on having dual memory card slots on their cameras.
    – xiota
    Jul 24 '19 at 22:40

The error can only be caused by 2 things:

  1. The image is of a different file type than it's extension - I've seen many situations when JPEG extension-files were actually PNGs or another different image format. Photoshop does not like opening files that don’t have the correct extension and will not.

  2. The image file is corrupted – This typically happens with JPEG files that are really small or have fixed-size block binary values (like 1024B, etc).

To determine in which situation you are in, just open one of the affected files with a text editor (even notepad is good). A valid JPEG will start with 6 ASCII-specifc characters followed by the string JFIF. If you see that, it means you have a valid JPEG file. If you see another ASCII character followed by the text PNG, then you actually have a PNG and you will have to rename the file from *.jpg to *.png. The file will become valid to be opened including in Photoshop.

If the start characters are totally random ASCII with no specific file type tag, then it will be clear that you deal with a corrupted file.

  • Don't open images in text editors. That's a great way to corrupt image files. The proper tools are hex viewers and file type identification programs.
    – xiota
    Jul 26 '19 at 21:12
  • @xiota do open, just don't save from within such editors.
    – Ruslan
    Jul 26 '19 at 21:13
  • @Ruslan Text editors are simply the wrong tool to use. Most text editors will corrupt the data. Many text editors have auto-save that will over write the original file with the newly corrupted data. Some text editors will recognize that the file is a binary file and display a blank document. Some text editors have file size limits.
    – xiota
    Jul 26 '19 at 21:17
  • @xiota marking the file as read-only will help avoid data corruption from such stupid editors which auto-save unchanged file. It's a must anyway if you don't want your files to be accidentally altered.
    – Ruslan
    Jul 26 '19 at 21:21
  • @Ruslan People have been known to edit images using MS Word. While it can be done, it's the wrong tool for the job. Use the right tools. Then you won't have to use workarounds to avoid and fix problems that are caused by using the wrong tools in the first place.
    – xiota
    Jul 26 '19 at 21:49

The typical cause for this problem is a thumb drive that was remarkably affordable for its capacity and has been manipulated to boast capacities it does not actually provide. As a result, new files randomly override pieces of older files which then become unreadable.


Agreeing with the others who described problems with USB drives and as a computer geek who belongs to those kind of forums...

I've encountered similar problems with new USB drives. You may want to use a stick that is 4GB or less or else format larger ones as exFAT. The normal FAT32 format used by many sticks are unable to handle large files containing high resolution photos and video unless reformatted as exFAT. You could also try reformatting the USB drive that you are already using as exFAT. If you are using a drive that you have used for years, then you probably should reformat it exFAT remembering that everything eventually wears out, so if reformatting doesn't work, maybe you just need a new USB drive.

Also, many new cameras can directly send files over wifi or bluetooth (you may have to download the full manual from the camera manufacturer website to see how because they don't always include it in the box, only a quick setup guide instead). If your camera doesn't include those features, like my slightly older model camera, you could use a device called eyefi, an SD card with its own built in WIFI that syncs very nicely with your phone, for upload to YouTube and other online galleries. Here is their website:

Hopes that helps and good luck.


Are you sure those aren't thumbnail files? Created either by the Samsung camera app, or some photo-related app that scans your photos and generates its own thumbnails?

If so, just don't copy them. You could also delete them (which I've always tended to do), if some app needed them, I haven't seen a photo-related app yet, that isn't smart enough to regenerate thumbnails if it needs them. (But just thumbnail images and no corresponding full image - e.g. you downloaded and deleted the originals - that more often causes problems.)

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